GTRoger Posted May 15, 2008 Share Posted May 15, 2008 Soon I'm going to convert my 2.5PI back from triple weber to the original PI system. Is it best to use the original Lucas fuel pump or the Bosch alternative?Thanks,Roger Link to comment Share on other sites More sharing options...
mikeyb Posted May 15, 2008 Share Posted May 15, 2008 Depends how much you want to spend Roger. I have a Bosch pump in the shed, but apart from my problems last Nachrict (which turned out to be due to bits in the tank rather than pump failure), I've had no problem with originals. I do have a large box of spares (some good, some bad) - I guess when this runs out I will fit the Bosch. Test the one you are going to fit, make sure the current and output pressure are acceptable. If they are and you have a good PRV then things should be ok. I've got a cooling coil on mine, but before I fitted it never suffered overheating anyway!Soldered battery lead connections and relay/dedicated power feed to the pump are also good reliability mods.Getting 27 mpg now!RegardsMike! Link to comment Share on other sites More sharing options...
andy thompson Posted May 16, 2008 Share Posted May 16, 2008 Bosch... get a new one. Fit and forget... just need a bigger outlet from the tank.You need the big pump too ... Volvo - Mercedes type Link to comment Share on other sites More sharing options...
Jason Posted May 16, 2008 Share Posted May 16, 2008 Pick your Bosch carefully, they aren't all the same :-) Personally I prefer the good old Lucas but it's not without the odd problem, especially if you pick one off the pile and expect it to work! The pump part of the unit seems to be pretty trouble free, it's the motor that's a pain. However, if you tune them they are OK, cooling coil, armature end float set as per factory and a good power supply sorted all my pump issues. Also, don't ignore the PRV, they ain't infallable and do lose their settings.Having said all that I've never heard of a Bosch pump overheating or causing cavitation type issues (vapour pulses in the lines) but I have heard of them dying through lack of use. Link to comment Share on other sites More sharing options...
Caroline Posted May 23, 2008 Share Posted May 23, 2008 MikeyB wrote:I've got a cooling coil on mine, but before I fitted it never suffered overheating anyway!My estate appears to have cavitation issues when it gets hot (over 30 mins thrashing!). It's a Lucas. Was planning to tour Scotland in it starting tomorrow but have now had to dig out an Acclaim (as you do). The pump was refurbd as part of the car's rebuild and has done very little use with us.So - what is this cooling coil, does it work, is Bosch better? Help! Link to comment Share on other sites More sharing options...
Jason Posted May 23, 2008 Share Posted May 23, 2008 A few things to check before you have at the pump - Air - make sure you've got some around the pump body, try and keep it clear of tools and other crap that might insulate it or keep the heat in.Filter - I know it's only just been fitted BUT new tank = new crap and I would always start with an examination of your filter - they are cheap as chips to replace so easy first fix attempt.Next is current draw of the pump - can't remember the settings now but you can "tune" the current draw by adjusting the end float - nut on the end so that the pump draws the min current. The higher the current draw the hotter the pump. Finally you're into a cooling coil - it's really simple and uses the spill back from the PRV (low pressure fuel) as coolant. You get some copper fuel pipe and coil it round the pump body - in practice find something a little smaller to use a former so that the resulting coil sits nice and tight against the pump. Now connect the spill from the PRV to one end of the coil and the other end of the coil to the old pipe that took the spill back to the tank. Voila! You have a cooling coil and all your troubles will be distant memories (yeah right :-) Link to comment Share on other sites More sharing options...
Jason Posted May 23, 2008 Share Posted May 23, 2008 Can't find a decent picture of one fitted, here's one un-fitted - will go take a pic later for you :-) Link to comment Share on other sites More sharing options...
Caroline Posted May 23, 2008 Share Posted May 23, 2008 Thanks JasonIt's got plenty of air around it as the boot floor is missing as is the spare wheel, so that's that.Will try a new fuel filter. Good shout.Any ideas what current the pump should take? Logical suggestion. Thanks.The cooling coil fitting doesn't sound like a 3 minute job, so we'll tackle that on our return.Is it worth mentioning the pump is making ooOOh ooOOh noises which sounds like the fuel in the tank is sloshing and the pump is getting it in surges. I think we'lve always had this problem but assumed it was a poorly baffled tank, not the pump struggling.(Is there a technical glossary of printing noises? I'm not doing a sound track to translate the above!) Link to comment Share on other sites More sharing options...
Jason Posted May 23, 2008 Share Posted May 23, 2008 Right, found it - 3.5 to 5 amps current draw. Referring ot the Lucas fault cards it also says check alternator belt tension :-) Link to comment Share on other sites More sharing options...
Jason Posted May 23, 2008 Share Posted May 23, 2008 I must get round to publishing all the fault cards, here's the check list that is quote useful Link to comment Share on other sites More sharing options...
Caroline Posted May 23, 2008 Share Posted May 23, 2008 OK, something to try. Thanks! Link to comment Share on other sites More sharing options...
Jason Posted May 23, 2008 Share Posted May 23, 2008 No problemo ;-) Link to comment Share on other sites More sharing options...
Jason Posted May 23, 2008 Share Posted May 23, 2008 Right - I have published all the fault cards especially for all PI owners out there :-)Enjoy http://chinn.blogspot.com/ Link to comment Share on other sites More sharing options...
Caroline Posted May 23, 2008 Share Posted May 23, 2008 Wow - such pretty colours! Link to comment Share on other sites More sharing options...
Jason Posted May 23, 2008 Share Posted May 23, 2008 They are lurid in real life, and laminated too! Link to comment Share on other sites More sharing options...
Richard B Posted May 23, 2008 Share Posted May 23, 2008 Caroline; be warned. PI Estates have more of a problem than PI Saloons. (I've owned two PI Estates on the road). The glass in the back of the cabin heats the floor up (above the pump). Summer and traffic jams is the worst combination!Definitely fit a cooling coil and keep the tank as full as possible. The coil works by dumping the heat from the pump into the fuel tank. As the tank runs down the low of diminishing returns kicks in. Link to comment Share on other sites More sharing options...
piman Posted May 24, 2008 Share Posted May 24, 2008 Hello Caroline, a point Jason did not mention (I think) is that of the supply voltage to the pump. With old switches and the safety switch contacts it's possible that the voltage is lower than desirable and this also contributes to pump overheating. Worth a check, and the ideal is to use a relay to feed the pump with decent sized cable.Alec Link to comment Share on other sites More sharing options...
Steve AKA vitessesteve Posted May 24, 2008 Share Posted May 24, 2008 Wire it up like this: http://www.vitessesteve.co.uk/PI_Project/PI_Project3.htm Link to comment Share on other sites More sharing options...
Jason Posted May 24, 2008 Share Posted May 24, 2008 piman wrote:Hello Caroline, a point Jason did not mention (I think) is that of the supply voltage to the pump. With old switches and the safety switch contacts it's possible that the voltage is lower than desirable and this also contributes to pump overheating. Worth a check, and the ideal is to use a relay to feed the pump with decent sized cable.AlecI didn't mention it and it's a fair point well made :-) I was surprised to see reference to the fan belt until I thought about it - PI is totally dependant on fuel pressure, insufficient pressure = problems including cutting out etc So if the pump is misbehaving then you'll get problems. It's not like carbs, there's no float chamber to smooth out the wrinkles! Link to comment Share on other sites More sharing options...
piman Posted May 24, 2008 Share Posted May 24, 2008 Hello Steve, very handy, a drawing is worth a thousand words.Alec Link to comment Share on other sites More sharing options...
Barry Acclaim Guru Posted May 25, 2008 Share Posted May 25, 2008 Thanks chapsthe loom on the PI is brand new, we have encountered this sort of problem B4, so we had a new one made just for this very reason.b Link to comment Share on other sites More sharing options...
GTRoger Posted May 26, 2008 Author Share Posted May 26, 2008 Finally found time to do some research about the Lucas PI system. Searching the web gives lots of aswers to many questions. Obviously not all experts agree! Personally I think the Bosch conversion is what I'm after. Sounds far more reliable than the original Lucas converted wipermotor ... So far I haven't found an example of a properly set up Bosch system. There is no Lucas gear in my car at the moment so I can start from scratch. I do have all original equipment in my spares car so got all the bits that might be required. Any suggestions for a set up are welcome. I've read some stuff about helper pumps and use of a surgetank. What about the PRV, is it ok to use the original one? From the electrical side of things I think the diagram as showed by Steve is usefull. Any idea where to get a new inertia switch from? Don't think I've got one.Thanks!Rogerbtw, this is it! My PI powerplant 8) Hopefully going in next weekend. Link to comment Share on other sites More sharing options...
Richard B Posted May 26, 2008 Share Posted May 26, 2008 This was from Prestige; had to do a couple of modifications and the main pipe had the wrong orientation for my application so I had a new pip made by Think Automotive. The 90 degree copper pipe was homemade, a better version was made later. Link to comment Share on other sites More sharing options...
Richard B Posted May 26, 2008 Share Posted May 26, 2008 You might want to do a re-pipe work job if you are comissioning a system; I bought 3/8 Kunifer pipe and some 3/8BSP female ends. Also the Sykes-Pickavant Flaring Tool proved bloody useful!I've just used the standard PRV for now, PI tank has integral swirl bowl. Link to comment Share on other sites More sharing options...
GTRoger Posted May 26, 2008 Author Share Posted May 26, 2008 Thanks for your help and pics Richard! Haven't checked the car underneath yet, I think the original returnpipes etc are still there. What's the blue thing on pic one? Link to comment Share on other sites More sharing options...
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